Rotary impact crusher

ABSTRACT

A rotary impact crusher for rock or the like has an impeller with a plurality of impeller blades, and a plurality of breaker plates. A pivotal cylindrically concave baffle extends along a segment of the blade orbit. The blades are inclined into the direction of impeller rotation at angles of 25* to 45* and have outside edges lying along the orbit. Strips of resilient material wedge the blades into channels in the impeller. Like blades are mounted on the baffle, the faces of these blades being positioned complementarily to the impeller blades.

United States Patent Inventor lFranz Wageneder Josei Grimps-Strasse 6, Laaltirchen, Austria Appl. No. 806,556 Filed Mar. 12, 1969 Patented Sept. 28, 1971 Priority Mar. 14, 1968 Austria A2,520/68 Continuation-impart oi application Ser. No. 665,448, Sept. 5, 1967, now llatent No. 3,480,214.

ROTARY IMPACT CRUSHER 10 Claims, 2 Drawing Figs.

11.8. C1 2411/189 R, 241/191, 241/195, 241/239 int. Cl ..B02c 13/00, B02c 13/28 Field of Search 241/86, 88,

[56] References Cited UNITED STATES PATENTS 1,189,471 7/1916 Ochterbeck 241/189 2,308,578 1/1943 White et a1. 241/86 2,585,943 2/1952 Kessler 241/191 2,647,695 8/1953 Rogers 241/197 Primary Examiner-Lester M. Swingle Assistant Examiner-Gary L. Smith Attorney- 1(arl F. Ross ABSTRACT: A rotary impact crusher for rock or the like has an impeller with a plurality of impeller blades, and a plurality of breaker plates. A pivotal cylindrically concave bafile extends along a segment of the blade orbit. The blades are inclined into the direction of impeller rotation at angles of 25 to 45 and have outside edges lying along the orbit. Strips of resilient material wedge the blades into channels in the 'impeller. Like blades are mounted on the bafi'le, the faces of these blades being positioned complementarily to the impeller blades.

ATENTEU 8EP2819?! Franz Wageneder INVENTOR.

ROTARY IMPACT CRUSHER This application is a continuation-in-part of my copending application Ser. No. 665,448, US. entitled Rotary Disintegrator," filed 5 Sept. 1967, now U.S. Pat. No. 3,480,214.

That application points out that a rotary disintegrator, such as a rock crusher or hammermill, serving for the comminution of solid materials into particles of predetermined maximum size, may have a curved grate extending along the orbit of a set of peripheral blades on a horizontally positioned rotor or impeller.

As this rotor turns on its axis, the grate defines with the blade orbit a clearance which converges in the direction of rotation and which subjects the larger fragments of the entrained solids to the crushing action of the blades acting against the bars of the grate. As long as the blades and the bars are relatively new, the width of this clearance can be easily maintained within the required tolerances. With progressive wear of the parts, however, the percentage of the finer particles passed by the grate diminishes and the yield of the disintegrator decreases. At the same time, an increasing proportion of the treated material experiences indirect grinding between other particles, rather than between the rotor blades and the grate, which adds to the frictional resistance encountered by the rotor, thus further lowering the efficiency of the system.

Although the aforedescribed drawbacks can be mitigated by a repeated readjustment of the grate with reference to the rotor, this solution is not entirely satisfactory because the parts do not wear so evenly that the original relationship can be restored by a change of position.

It was, therefore, the general object of the invention described in my application Ser. No. 665,448 to provide an improved disintegrator of the type described in which the aforestated disadvantages are avoided.

I have found, as described in my prior application, that the wear of the disintegrator parts engaged in the crushing process (i.e. the rotor blades and the grate bars) can be materially retarded if the single converging clearance heretofore provided between the grate and the blade orbit is subdivided into two consecutive clearances formed between that orbit and two separate curved grates. The first grate will then serve mainly for a coarse precomminution with separation of all the fine particle sizes as well as entrained sand, rubble and the like from the bulk of the mass; the second grate then receives the already precomminuted material so that it, too, does not have to perform more than a fraction of the task conventionally as signed to a single grate.

Thus, according to an important feature of my prior appli cation, the two grates are so disposed that the discharge end of the clearance formed between the first grate and the blade orbit, which can be substantially constant width, is narrower than the entrance end of the converging clearance defined by the second grate and the orbit, the two clearances being separated by small peripheral gap which preferably is located at the nadir of the rotor. Through this gap, as well as through the spaces between the bars of the first grate, drop the particles which do not require further comminution; the other, heavier fragments are accelerated sufiiciently to clear the gap and are intercepted by the second grate for further entrainment and grinding.

Thus, the first grate may extend along the lower quadrant of the blade orbit at the descending side of the blades while the second grate hugs the lower quadrant on the ascending side, this latter grate having its entrance edge disposed at a level lower than that of a confronting discharge edge of the first grate so as to lie beneath the trajectories of the heavier particles emerging more or less horizontally from the outlet end of the first clearance. Fragments that are not sufficiently comminuted even at the second grate leave the second clearance in a generally upward direction and are intercepted by an inclined deflector plate (including an angle of, say, to 30 with the horizontal) directing them away from the rotor so as to prevent their further entrainment. These latter particles, which may include foreign bodies resistant to the crushing action of the rotor blades, may be caused to drop into a separate receptacle or, if commingled with the remainder of the comminuted mass, may be subsequently removed therefrom by sifting.

Conventional electric and/or magnetic checking devices may be used, of course, at the input of the disintegrator to detect and remove metallic objects. Nevertheless, large refractory chunks may on occasion enter the system and interfere with its proper operation; for this reason l prefer to provide an independent resilient mounting for each grate, advantageously with biasing springs urg'ng the grates toward the rotor and detent means, e.g. in the form of screws, positively limiting the extent of such displacement. By pivotally supporting the first grate for swinging movement about an axis at or slightly above the level of the rotor axis, lcan readily vary the effective width of the first clearance and also compensate for wear. The second grate, advantageously, may be mounted on a carriage within a compartment separated by a partition from the grind ing chamber of the disintegrator, this carriage allowing for both horizontal and vertical as well as angular adjustment of that grate to facilitate changing the width of the integrate gap and varying the effective width and rate of convergence of the second clearance.

For purposes of ease of accessibility in the case of inspection, replacement or repair. I prefer to subdivide the disintegrator housing into two portion substantially along a plane vertically bisecting the rotor, the two portions being normally locked to each other by manually or otherwise disengageable mating formations such as a set of slotted lugs cooperating with respective tenons. When detached from each other, the portions may be moved apart to accommodate, for example, a working platform that may be suspended from an overhead crane or may be rested on the split housing portions. In this manner, access can also be had to a breaker plate carried on the support for the first grate, this plate being preferably symmetrical and, therefore, reusable in a reversed position after unilateral wear.

Another feature of previous invention resides in the provision of an elevated base supporting the rotor and its drive motor, this base lying for the most part near the level of the rotor axis so as not to interfere with the swingable support for the first grate. In the region of the rotor axis the base forms a pair of dependent yokes carrying bearings for the rotor shaft. Advantageously, the base consists of a pair of rails, integral with the aforementioned yokes, for the guidance of the movable housing portion.

Furthermore, it has been found that wear of the blades on the rotor or impeller and of the rails on the grate or baffle is sizable. This is generally due to the fact that the portion of the blades that projects from the impeller and is intended to impinge the rocks is generally square or rectangular in cross section and has faces in line with a radius drawn to the impeller rotation axis. Thus the blade corners very quickly wear off this blade, thereby making it round. This makes the blades highly inefficient for slinging the rocks against the breaker plates and for advancing the rocks around through the crusher.

Even though these blades are often made to be reversible, they must be frequently replaced to keep output of the machine up, thereby leading to high operating expenses. Furthermore, the rails of the grate also tend to wear out and need periodic replacement.

When, in order to produce sand, a very find grate or a simple closed bafile is used, such blades are even more greatly stressed and more quickly rounded, so that replacement is required more often.

It is therefore the principal object of my present invention to provide a rotary impact crusher that overcomes these above-described and other disadvantages.

Another object is to provide such a crusher wherein the amount of wear is sizably reduced in both the blades of the impeller and the rails of the baffle.

l attain these and other objects, in accordance with a key feature of my present invention, by providing a blade arrange ment on my rotary crusher wherein the leading face of the blade is inclined with respect to the radius into the direction of rotation of the impeller by 2545. The trailing face of the blade is parallel to the leading face, and the outward facing edge between them is roughly tangential to or lies along an arc of their orbit, facing away from the rotation axis of the impeller.

The blade according to my present invention has a narrow waist and outer blade portions of parallelogrammatic cross section. The blade is adapted to be reversed once one said is worn down. To do this it is mounted between two elongated keys in what amounts to a groove on the impeller.

In additions, the trailing edge of the blade is buttressed by a resilient strip so that a slight amount of the strain the blade is subjected to can be absorbed here. This prevents to a remarkable extend, the danger of breaking of the blade, even if some relatively uncrushable material is fed into the crusher.

According to a further feature of my invention, the baffle is also provided with similar blades. These blades face back into the directions of rotation of the impeller at the same angle as the impeller blades. In practice, the blades which have been used on both sides in the impeller are employed here in the bafile. This allows each blades to be fully consumed and sizably reduces running costs.

Although my invention is equally applicable to crushers impeller-disintegrators with one or two separate pivotal bafiles or grates, I have found that with a one-bafile crusher provided with an impeller according to my invention the crushed or comminuted particles are thrown off at very high speeds. Although these particles, in one embodiment of my invention, are only about 3 mm. in diameter-thus constituting coarse sand this presents a danger to the crusher walls. I overcome this, in accordance with another feature of my invention, by offsetting the downstream wall of the crusherthe wall adjacent the ascending side of the impeller and providing a low partition extending part of the way up in the crusher between the impeller and that wall. Thus a wall or lining of sand or crushed rock to a thickness of the order of 0.5 m. builds up between this partition and the wall to protect the latter from harm by the particles thrown against it.

These features make for a crusher having the advantages of a high output of finely ground product, and relatively low operating cost due to the long service life of the blades used both on the impeller and on the baffle.

These and other objects, features, and advantages will be described in the following with reference to the drawing, in which:

FIG. 1 is a cross section through part of an impeller having a blade arrangement in accordance with my invention, and

FIG. 2 is a horizontal section through a rotary crusher according to my invention, with the impeller-blade arrangement shown in FIG. 1.

As shown in FIG. 2 a rotary crusher has a housing 16 with a pivotal top 16b and a downstream wall 16a. Rock or the like to be crushed is loaded into the mouth 23 where it is retained temporarily by a thick rubber curtain 22a and a chain curtain 22b. Thence it is crushed, as will be more fully described below, and the final comminuted product exits through opening 24.

This crusher is intended to reduce rocky material into reasonably fine sandy material having a particle size of about 3 mm. Thus the input is normal rock of a degree of hardness from soft up to quite hard, and the output is an even sand.

After passing the curtains 22a and 22b, the rock is flung by a spinning impeller 10 against a series of breaker plates 21. This effectively smashes the large fragments. Then the impeller 10 crushes them against a mill plate 14 or a baffle 13 pivoted at 12. The clearance between the orbit of the impeller and the mill plate 14 is set by a screw arrangement which pivots the baffle 13. This baffle 13 consists of two arms 130 between which a plurality of rails 15 extend, with two blades 1 as will be described below.

As the partially fragmented rock is carried around against the baffle 13 by the impeller 10 it is fully milled and reduced to the desired size. Then it is projected in the form of a hail of particles against the downstream wall 16a of the housing 16. To prevent harm to this wall it is well ofi'set from the impeller 10 and a small partition wall 17 is provided on the bottom of the housing 16 next to the outlet 24. Because of this partition 17, a mount 19 of comminuted material builds up, with a wall 18 of the inlet 23 as the upper limit to this particle catching compartment, that protects the wall 16a.

FIG. 1 shows the blade arrangement on the impeller 10 in more detail. Here it can be seen that the impeller 10 consists of a plurality of plates 10a (only one shown) arranged on bars 25 and rotatable with a driven shaft 11 about a horizontal axis A. The plate 10a, is formed with a notch 10b that makes for a sort of axial channel across the impeller 10.

This channel formed by the notches 10b holds one of the blades 1. This has two relatively large end portions la, and 1b separated by a relatively narrow waist 10c. The end In projecting from the impeller 10 has a leading face ld, a trailing face 1f, and an outer face 1e. The faces ldtand l f, lie parallel to each other at 32 to a radius R from the axis A. The face le, lies tangential to the orbit o. The waist 10, is gripped between two keys 3 and 4 held by screws 5 and 6. A strip 2 of black rubber lies behind a flank 1a, of the blade 1, relative to the rotation directions, and cushions it. The flanks 1a, of each parallelogrammatic blade body extend orthogonally at right angles) to the trailing faces and terminate at flanks lc,defining the waist and parallel to the radius R. Flanks la, constitute the supporting shoulders of the blade and lie diagonally opposite the forward cutting edge (defined between the leading face 1d and face 1e) Only two screws 5 are required in the impeller for each blade; they serve simply to hold the key 4 up when the blade 1 is being changed. A bolt 7 holds a plate 9 which protects the impeller 10 while the bolt 6 passes through a plate 8 for the same purpose. A plate 26 held by the plate 9 acts upon a lip 3a of the key 3 as the plate 50 on a lip 40 of the key 4 to hold the keys 3 and 4 with the blade 1 in the notch 10b. It is also worth noting that the blade 1 can move with the keys 3 and 4 toward the axis A due to the depth of the notch 10b.

When thoroughly worn down or one end is worn down, the blades 1 are merely pulled axially out from between the keys 3 and 4, centrifugal force holding them firmly in place during operation of the crusher. Once each blade 1 has been used on both ends 1a and 1b, it is slid into the arms 13a of the baffle 13 and fully used up there. The plates 8 and 9 must also be periodically replaced.

Such an arrangement of blades 1 on both the impeller 10 and on the baffle 13 causes the blades to sharpen each other. This is due mainly to the fact that the blades on the impeller 10 are raked forward into the direction of rotation, while those on the baffle 13 are raked back.

I claim:

1. A rotary impact crusher comprising an impeller rotatable about a horizontal axis and provided with at least one axially extending impeller blade projecting outwardly of said impeller, and a cylindrically concave baffle defining a clearance with the blade orbit, said blade having, in the rotational direction, a leading face inclined into the direction of rotation at an angle of 25 to 45 to a radius running from said axis to said blade, said baffle having at least one such blade having one such leading face inclined counter to the direction of rotation of the impeller at an angle of 25 to 45 to a radius running from said axis to said blade of said battle.

2. The rotary impact crusher defined in claim 1 wherein said blade of said impeller has a trailing face substantially parallel to said leading face.

3. The rotary impact crusher defined in claim 2 wherein said blade of said impeller has an outer face directed away from said axis and lying substantially along an arc of said orbit.

4. The rotary impact crusher defined in claim 1 wherein said impeller is provided with a channel partially receiving and mounting the impeller blade and a resilient band in said channel behind said impeller blade with respect to the rotational direction.

5. The rotary impact crusher defined in claim d, further comprising a wedge locking said blade in said impeller channel.

6. The rotary impact crusher defined in claim d wherein said impeller blade has a longitudinally extending narrow waist between two relatively large outer portions each having said leading, trailing and outer face, whereby said impeller blade can be reversed in said channel and is adapted to be clamped at said waist.

7. The rotary impact crusher defined in claim 11 wherein said baffle is pivotal to vary said clearance.

8. The rotary impact crusher defined in claim ll wherein said crusher further comprises a housing having a sidewall on the ascending side of said impeller with respect to the rotational direction thereof, a bottom wall, and an upright partition extending partially upwardly in said housing from said bottom wall and spaced from said sidewall and defining a particleretaining compartment with said sidewall and defining a particle-retaining compartment with said sidewall adapted to accumulate said particles and form a relatively thick lining for said sidewall therefrom.

9. The rotary impact crusher defined in claim b wherein said impeller is of parrallelogrammatic cross section and said lining has a thickness of the order off 0.5 m, said partition having a height of at least 0.5 m and lying within the projection of the impeller on said bottom wall while reaching upwardly to a distance between about 11 and about 3 impeller diameters therefrom.

it). A rotary impact mill comprising a housing having an inlet for material to be crushed; an impeller rotatable about a horizontal axis; a plurality of angularly spaced axially extending blades mounted in said impeller and projecting beyond the periphery thereof, said blades describing a circular orbit centered on said axis; a plurality of braker plates spaced apart above said impeller and intercepting the material entrained thereby to comminute the same by impact forces; and an arcuate baffle extending beneath said impeller and along an arc segment, said baffle being provided with a mill plate cooperating with said impeller blades for crushing said material and with at least one baffle blade extending parallel to the axis and projecting in the direction of said orbit, said impeller blades having parallel leading and trailing faces inclined into the direction of rotation and said baffle blade having parallel leading and trailing faces inclined counter to the direction of rotation of said impeller, said faces including acute angles between 25 and 45 with a plane of the axis along a radius of the orbit. 

1. A rotary impact crusher comprising an impeller rotatable about a horizontal axis and provided with at least one axially extending impeller blade projecting outwardly of said impeller, and a cylindrically concave baffle defining a clearance with the blade orbit, said blade having, in the rotational direction, a leading face inclined into the direction of rotation at an angle of 25* to 45* to a radius running from said axis to said blade, said baffle having at least one such blade having one such leading face inclined counter to the direction of rotation of the impeller at an angle of 25* to 45* to a radius running from said axis to said blade of said baffle.
 2. The rotary impact crusher defined in claim 1 wherein said blade of said impeller has a trailing face substantially parallel to said leading face.
 3. The rotary impact crusher defined in claim 2 wherein said blade of said impeller has an outer face directed away from said axis and lying substantially along an arc of said orbit.
 4. The rotary impact crusher defined in claim 1 wherein said impeller is provided with a channel partially receiving and mounting the impeller blade and a resilient band in said channel behind said impeller blade with respect to the rotational direction.
 5. The rotary impact crusher defined in claim 4, further comprising a wedge locking said blade in said impeller channel.
 6. The rotary impact crusher defined in claim 4 wherein said impeller blade has a longitudinally extending narrow waist between two relatively large outer portions each having said leading, trailing and outer face, whereby said impeller blade can be reversed in said channel and is adapted to be clamped at said waist.
 7. The rotary impact crusher defined in claim 1 wherein said baffle is pivotal to vary said clearance.
 8. The rotary impact crusher defined in claim 1 wherein said crusher further comprises a housing having a sidewall on the ascending side of said impeller with respect to the rotational direction thereof, a bottom wall, and an upright partition extending partially upwardly in said housing from said bottom wall and spaced from said sidewall and defining a particle-retaining compartment with said sidewall and defining a particle-retaining compartment with said sidewall adapted to accumulate said particles and form a relatively thick lining for said sidewall therefrom.
 9. The rotary impact crusher defined in claim 8 wherein said impeller is of parrallelogrammatic cross section and said lining has a thickness of the order off 0.5 m., said partition having a height of at least 0.5 m. and lying within the projection of the impeller on said bottom wall while reaching upwardly to a distance between aboUt 1 and about 3 impeller diameters therefrom.
 10. A rotary impact mill comprising a housing having an inlet for material to be crushed; an impeller rotatable about a horizontal axis; a plurality of angularly spaced axially extending blades mounted in said impeller and projecting beyond the periphery thereof, said blades describing a circular orbit centered on said axis; a plurality of braker plates spaced apart above said impeller and intercepting the material entrained thereby to comminute the same by impact forces; and an arcuate baffle extending beneath said impeller and along an arc segment, said baffle being provided with a mill plate cooperating with said impeller blades for crushing said material and with at least one baffle blade extending parallel to the axis and projecting in the direction of said orbit, said impeller blades having parallel leading and trailing faces inclined into the direction of rotation and said baffle blade having parallel leading and trailing faces inclined counter to the direction of rotation of said impeller, said faces including acute angles between 25* and 45* with a plane of the axis along a radius of the orbit. 